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Jul 22, 2015
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74 changes: 73 additions & 1 deletion src/libstd/io/buffered.rs
Original file line number Diff line number Diff line change
Expand Up @@ -269,6 +269,27 @@ pub struct BufWriter<W: Write> {
/// An error returned by `into_inner` which combines an error that
/// happened while writing out the buffer, and the buffered writer object
/// which may be used to recover from the condition.
///
/// # Examples
///
/// ```no_run
/// use std::io::BufWriter;
/// use std::net::TcpStream;
///
/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
///
/// // do stuff with the stream
///
/// // we want to get our `TcpStream` back, so let's try:
///
/// let stream = match stream.into_inner() {
/// Ok(s) => s,
/// Err(e) => {
/// // Here, e is an IntoInnerError
/// panic!("An error occurred");
/// }
/// };
/// ```
#[derive(Debug)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct IntoInnerError<W>(W, Error);
Expand Down Expand Up @@ -384,16 +405,67 @@ impl<W: Write> Drop for BufWriter<W> {
}

impl<W> IntoInnerError<W> {
/// Returns the error which caused the call to `into_inner` to fail.
/// Returns the error which caused the call to `into_inner()` to fail.
///
/// This error was returned when attempting to write the internal buffer.
///
/// # Examples
///
/// ```no_run
/// use std::io::BufWriter;
/// use std::net::TcpStream;
///
/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
///
/// // do stuff with the stream
///
/// // we want to get our `TcpStream` back, so let's try:
///
/// let stream = match stream.into_inner() {
/// Ok(s) => s,
/// Err(e) => {
/// // Here, e is an IntoInnerError, let's log the inner error.
/// //
/// // We'll just 'log' to stdout for this example.
/// println!("{}", e.error());
///
/// panic!("An unexpected error occurred.");
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Perhaps the e.error() could be used in the panic message here instead of printing out?

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So, the reason I didn't do that was that then the example is just unwrap()...

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Ah, right

/// }
/// };
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn error(&self) -> &Error { &self.1 }

/// Returns the buffered writer instance which generated the error.
///
/// The returned object can be used for error recovery, such as
/// re-inspecting the buffer.
///
/// # Examples
///
/// ```no_run
/// use std::io::BufWriter;
/// use std::net::TcpStream;
///
/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
///
/// // do stuff with the stream
///
/// // we want to get our `TcpStream` back, so let's try:
///
/// let stream = match stream.into_inner() {
/// Ok(s) => s,
/// Err(e) => {
/// // Here, e is a IntoInnerError, let's re-examine the buffer:
/// let buffer = e.into_inner();
///
/// // do stuff to try to recover
///
/// // afterwards, let's just return the stream
/// buffer.into_inner().unwrap()
/// }
/// };
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn into_inner(self) -> W { self.0 }
}
Expand Down